ADDIS ABABA UNIVERSITY SCHOOL OF GRADUATE STUDIES FACULTY OF TECHNOLOGY DEPARTMENT OF CIVIL ENGINEERING RESERVOIR OPERATION AND ESTABLISHMENT OF OPERATION RULES FOR LAKE TANA Thesis Submitted to the School of Graduate Studies in Partial Fulfillment of the Requirements for the Degree of Master of Science In Civil Engineering (Major in Hydraulic Engineering) By Melkamu Amare Aragie January 2005 ADDIS ABABA UNIVERSITY SCHOOL OF GRADUATE STUDIES FACULTY OF TECHNOLOGY DEPARTMENT OF CIVIL ENGINEERING RESERVOIR OPERATION AND ESTABLISHMENT OF OPERATION RULES FOR LAKE TANA By Melkamu Amare Aragie January 2005 Approved by Board of Examiners Dr Ing Abdulkerim Hussein Seid __________________ _________________ Advisor Signature Date Ato Deksios Tarekegne _____________________ __________________ External Examiner Signature Date Dr Bayou Chane_________ _____________________ _________________ Internal Examiner Signature Date Dr Ing Yonas Michael______ _____________________ __________________ Chairman Signature Date ________________________________________________________________________ ACKNOWLEDGMENTS I am grateful to express my sincere thanks to my Advisor Dr.Ing Abdulkerim Seid, Assistant Professor of Civil Engineering, Addis Ababa University who devoted his time to guide and assist me in the process of the thesis work. With out him this research work wouldn’t have this final form. I would like to thank all staffs in the Ministry of Water Resources especially to those staffs in the Departments of Hydrology and Data Base, National Metrological Service Agency and Ethiopian Electric Power Corporation, for providing me with related materials. I am grateful to the Addis Ababa University Civil Engineering Department Staff, my family and class mates for their material and moral support. Finally my special thanks goes to Yohannis Daniel, member of the AAU, Water Resources Research Centre for assisting me in operating the ArcView GIS software. vii TABLE OF CONTENTS ACKNOWLEDGMENTS............................................................................................................................ iv TABLE OF CONTENTS ................................................................................................................................ ii ABSTRACT .................................................................................................................................................viii 1. INTRODUCTION .................................................................................................................................... 1 1.1 Background..................................................................................................................................... 1 1.2 Problem Statement.......................................................................................................................... 3 1.3 Objectives ....................................................................................................................................... 4 1.4 Methodology................................................................................................................................... 5 2 THE STUDY AREA AND AVAILABLE DATA BASE........................................................................ 6 2.1 Location .......................................................................................................................................... 6 2.1.1 Administrative Location .............................................................................................................. 6 2.1.2 Geographical Location................................................................................................................. 6 2.2 Physical Features ............................................................................................................................ 6 2.2.1 Topography and Drainage ........................................................................................................... 6 2.2.2 Climate and Rainfall................................................................................................................... 9 2.2.3 Water Resources ........................................................................................................................ 13 2.3 Geological Settings....................................................................................................................... 14 2.3.1 Formations Occurring at Lake Tana.......................................................................................... 14 2.3.2 Geological Impact as a Result of Regulation .......................................................................... 14 2.3.3 Sedimentation .......................................................................................................................... 15 2.3.4 Seepage..................................................................................................................................... 15 2.3.5 Land Resources.......................................................................................................................... 15 2.4 Socio Economic Features ............................................................................................................. 16 2.4.1 Population.................................................................................................................................. 16 2.4.2 Economic Activities................................................................................................................... 16 2.5 The Available Data Base .............................................................................................................. 17 2.5.1 Hydrologic Data......................................................................................................................... 17 2.5.2 Climatic Data............................................................................................................................. 18 2.5.3 Hydropower Related Data ......................................................................................................... 19 2.5.4 Socioeconomic Data .................................................................................................................. 19 2.5.5 Crop Husbandry Data ................................................................................................................ 19 2.6 Water Resources Potential and Current Level of Utilization ....................................................... 21 2.6.1 Potential for Irrigated Agriculture Development....................................................................... 21 2.6.2 Potential for Hydropower Development.................................................................................... 22 2.6.3 Other Development Potentials................................................................................................... 22 3. PREVIOUS STUDIES............................................................................................................................ 23 3.1 General.......................................................................................................................................... 23 3.2 USBR Studies (1964) ................................................................................................................... 23 3.3 Tana-Beles Study (Studio Peterngeli, 1990) ................................................................................. 25 3.4 Abbay River Basin Integrated Master Plan Studies (BCEOM & Associates, 1998-99)............... 27 3.5 The Lahmayer International (LI) Study (August 2003) ............................................................... 28 3.6 Important Conclusions and Remarks............................................................................................ 28 i 4 PRELIMINARY DATA ANALYSIS .................................................................................................... 34 4.1 Aspects of Data Quality................................................................................................................ 34 4.1.1 Hydrologic Data......................................................................................................................... 34 4.1.2 Climatic Data............................................................................................................................. 34 4.2 Data Treatment ............................................................................................................................. 34 4.2.1 Hydrometric Data ...................................................................................................................... 34 4.2.2 Meteorological Data .................................................................................................................. 36 4.3 Preliminary Level Data Analysis.................................................................................................. 38 4.3.1 Rainfall ...................................................................................................................................... 38 4.3.3 Wind Speed at Bahir Dar........................................................................................................... 39 4.3.4 Lake Water Surface Level and Area.......................................................................................... 40 4.3.5 Lake Storage .............................................................................................................................